The study says "Among 3958 participants enrolled in the v-safe pregnancy registry, 827 had a completed pregnancy, of which 115 (13.9%) resulted in a pregnancy loss and 712 (86.1%) resulted in a live birth (mostly among participants with vaccination in the third trimester)."
What happened to the 79% that did not complete their pregnancy? That's what I want to know.
This a preliminary report, not a completed study. The Data was gathered just 4 weeks after the last participants were enrolled, and just 11 weeks after the first participant was enrolled. Many will have been born (and probably a few more miscarriages) in the 3 months since March 30, but many of the women are still pregnant. The last babies in the study won't be born until November 2021.